Well, Comodo's had an okay track-record, if I recall correctly. But I also don't recall them being cheap.
I am not sure what standards apply to companies in this segment, but Comodo has an awful track record imho. Just looking at the Wikipedia article gives me a shill. And those are only the cases where Comodo couldn't deny any wrongdoing or failure.
(Registration authorities are third parties that perform certificate validation on behalf of the CA. I think Comodo bears some responsibility for delegating validation to an RA that was compromised, but Symantec's conduct has been so much worse in comparison.)
And maybe you should disclose that you are a Comodo reseller.